/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.voicemail.impl.utils;

import android.util.ArrayMap;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;

public class XmlUtils {

  public static final ArrayMap<String, ?> readThisArrayMapXml(
      XmlPullParser parser, String endTag, String[] name, ReadMapCallback callback)
      throws XmlPullParserException, java.io.IOException {
    ArrayMap<String, Object> map = new ArrayMap<>();

    int eventType = parser.getEventType();
    do {
      if (eventType == XmlPullParser.START_TAG) {
        Object val = readThisValueXml(parser, name, callback, true);
        map.put(name[0], val);
      } else if (eventType == XmlPullParser.END_TAG) {
        if (parser.getName().equals(endTag)) {
          return map;
        }
        throw new XmlPullParserException("Expected " + endTag + " end tag at: " + parser.getName());
      }
      eventType = parser.next();
    } while (eventType != XmlPullParser.END_DOCUMENT);

    throw new XmlPullParserException("Document ended before " + endTag + " end tag");
  }

  /**
   * Read an ArrayList object from an XmlPullParser. The XML data could previously have been
   * generated by writeListXml(). The XmlPullParser must be positioned <em>after</em> the tag that
   * begins the list.
   *
   * @param parser The XmlPullParser from which to read the list data.
   * @param endTag Name of the tag that will end the list, usually "list".
   * @param name An array of one string, used to return the name attribute of the list's tag.
   * @return HashMap The newly generated list.
   */
  public static final ArrayList readThisListXml(
      XmlPullParser parser,
      String endTag,
      String[] name,
      ReadMapCallback callback,
      boolean arrayMap)
      throws XmlPullParserException, java.io.IOException {
    ArrayList list = new ArrayList();

    int eventType = parser.getEventType();
    do {
      if (eventType == XmlPullParser.START_TAG) {
        Object val = readThisValueXml(parser, name, callback, arrayMap);
        list.add(val);
      } else if (eventType == XmlPullParser.END_TAG) {
        if (parser.getName().equals(endTag)) {
          return list;
        }
        throw new XmlPullParserException("Expected " + endTag + " end tag at: " + parser.getName());
      }
      eventType = parser.next();
    } while (eventType != XmlPullParser.END_DOCUMENT);

    throw new XmlPullParserException("Document ended before " + endTag + " end tag");
  }

  /**
   * Read a String[] object from an XmlPullParser. The XML data could previously have been generated
   * by writeStringArrayXml(). The XmlPullParser must be positioned <em>after</em> the tag that
   * begins the list.
   *
   * @param parser The XmlPullParser from which to read the list data.
   * @param endTag Name of the tag that will end the list, usually "string-array".
   * @param name An array of one string, used to return the name attribute of the list's tag.
   * @return Returns a newly generated String[].
   */
  public static String[] readThisStringArrayXml(XmlPullParser parser, String endTag, String[] name)
      throws XmlPullParserException, java.io.IOException {

    parser.next();

    List<String> array = new ArrayList<>();

    int eventType = parser.getEventType();
    do {
      if (eventType == XmlPullParser.START_TAG) {
        if (parser.getName().equals("item")) {
          try {
            array.add(parser.getAttributeValue(null, "value"));
          } catch (NullPointerException e) {
            throw new XmlPullParserException("Need value attribute in item");
          } catch (NumberFormatException e) {
            throw new XmlPullParserException("Not a number in value attribute in item");
          }
        } else {
          throw new XmlPullParserException("Expected item tag at: " + parser.getName());
        }
      } else if (eventType == XmlPullParser.END_TAG) {
        if (parser.getName().equals(endTag)) {
          return array.toArray(new String[0]);
        } else if (parser.getName().equals("item")) {

        } else {
          throw new XmlPullParserException(
              "Expected " + endTag + " end tag at: " + parser.getName());
        }
      }
      eventType = parser.next();
    } while (eventType != XmlPullParser.END_DOCUMENT);

    throw new XmlPullParserException("Document ended before " + endTag + " end tag");
  }

  private static Object readThisValueXml(
      XmlPullParser parser, String[] name, ReadMapCallback callback, boolean arrayMap)
      throws XmlPullParserException, java.io.IOException {
    final String valueName = parser.getAttributeValue(null, "name");
    final String tagName = parser.getName();

    Object res;

    if (tagName.equals("null")) {
      res = null;
    } else if (tagName.equals("string")) {
      String value = "";
      int eventType;
      while ((eventType = parser.next()) != XmlPullParser.END_DOCUMENT) {
        if (eventType == XmlPullParser.END_TAG) {
          if (parser.getName().equals("string")) {
            name[0] = valueName;
            return value;
          }
          throw new XmlPullParserException("Unexpected end tag in <string>: " + parser.getName());
        } else if (eventType == XmlPullParser.TEXT) {
          value += parser.getText();
        } else if (eventType == XmlPullParser.START_TAG) {
          throw new XmlPullParserException("Unexpected start tag in <string>: " + parser.getName());
        }
      }
      throw new XmlPullParserException("Unexpected end of document in <string>");
    } else if ((res = readThisPrimitiveValueXml(parser, tagName)) != null) {
      // all work already done by readThisPrimitiveValueXml
    } else if (tagName.equals("string-array")) {
      res = readThisStringArrayXml(parser, "string-array", name);
      name[0] = valueName;
      return res;
    } else if (tagName.equals("list")) {
      parser.next();
      res = readThisListXml(parser, "list", name, callback, arrayMap);
      name[0] = valueName;
      return res;
    } else if (callback != null) {
      res = callback.readThisUnknownObjectXml(parser, tagName);
      name[0] = valueName;
      return res;
    } else {
      throw new XmlPullParserException("Unknown tag: " + tagName);
    }

    // Skip through to end tag.
    int eventType;
    while ((eventType = parser.next()) != XmlPullParser.END_DOCUMENT) {
      if (eventType == XmlPullParser.END_TAG) {
        if (parser.getName().equals(tagName)) {
          name[0] = valueName;
          return res;
        }
        throw new XmlPullParserException(
            "Unexpected end tag in <" + tagName + ">: " + parser.getName());
      } else if (eventType == XmlPullParser.TEXT) {
        throw new XmlPullParserException(
            "Unexpected text in <" + tagName + ">: " + parser.getName());
      } else if (eventType == XmlPullParser.START_TAG) {
        throw new XmlPullParserException(
            "Unexpected start tag in <" + tagName + ">: " + parser.getName());
      }
    }
    throw new XmlPullParserException("Unexpected end of document in <" + tagName + ">");
  }

  private static final Object readThisPrimitiveValueXml(XmlPullParser parser, String tagName)
      throws XmlPullParserException, java.io.IOException {
    try {
      if (tagName.equals("int")) {
        return Integer.parseInt(parser.getAttributeValue(null, "value"));
      } else if (tagName.equals("long")) {
        return Long.valueOf(parser.getAttributeValue(null, "value"));
      } else if (tagName.equals("float")) {
        return Float.valueOf(parser.getAttributeValue(null, "value"));
      } else if (tagName.equals("double")) {
        return Double.valueOf(parser.getAttributeValue(null, "value"));
      } else if (tagName.equals("boolean")) {
        return Boolean.valueOf(parser.getAttributeValue(null, "value"));
      } else {
        return null;
      }
    } catch (NullPointerException e) {
      throw new XmlPullParserException("Need value attribute in <" + tagName + ">");
    } catch (NumberFormatException e) {
      throw new XmlPullParserException("Not a number in value attribute in <" + tagName + ">");
    }
  }

  public interface ReadMapCallback {

    /**
     * Called from readThisMapXml when a START_TAG is not recognized. The input stream is positioned
     * within the start tag so that attributes can be read using in.getAttribute.
     *
     * @param in the XML input stream
     * @param tag the START_TAG that was not recognized.
     * @return the Object parsed from the stream which will be put into the map.
     * @throws XmlPullParserException if the START_TAG is not recognized.
     * @throws IOException on XmlPullParser serialization errors.
     */
    Object readThisUnknownObjectXml(XmlPullParser in, String tag)
        throws XmlPullParserException, IOException;
  }
}